Air-circulatory system for dry kilns



- c. PHILLIPS ET AL AIR CIRCULATQRY SYSTEM FOR DRY KILNS Nov. 10, 1936.

Filed Dec. 14, 1935 INVENTORS. a) I. n 5 V FI JJI Patented Nov. 10, 1936 UNITED STATES PATENT OFFICE Charles Phillips and George M. Harris, Louisville, Ky.

Application December 14, 1935, Serial No. 54,370

1 Claim.

Our invention relates to ways and means of providing for the introduction and the proper circulation of the fresh outer air with the inner heated air of a dry kiln, so that the lumber therein may be more quickly dried than it now is in the present types of dry kilns.

The principal objects of our invention are: First, to provide the ways and means for forcing into the front end of a dry kiln and through its upper portion a certain quantity of the fresh outer air to mix energetically in the circulatory system with the heated air in the dry kiln; second, to design a rail-track through the dry kiln and a plurality of lumber-trucks adapted to roll thereon; third, to design an efiicient steamboiler-radiator for said dry kiln, composed of a system of steam pipes, valves and their manifold connections arranged in flat-rack formation and extending horizontally the length and breadth of said dry-kiln, below said track-rails; fourth, to provide ample basement-space under said rail-track and lumber-trucks, the full length and width of said kiln for the complete circulation of the fresh outer air mingled with the inner heated air so that the mixture may be uniformly heated by said radiator to circulate through the lumber on said trucks; and fifth, to provide in the front wall of said basementspace near the bottom thereof a plurality of vents having adjustable vent-racks therein for the escape of the cool damp vapors of the kiln.

All these objects are attained in our present invention; and our new and useful air-circulatory system for dry kilns is a practically efficient system operative through the aforesaid novel means and other new and useful details of construction, arrangement and combination of parts, all of which, together with their functions, will be described in detail with reference to the accompanying drawing and will be definitely pointed out in the claim that follows the description.

In this specification, therefore, Figure I is a side elevation of a dry kiln in which our new circulatory system is operative, the side wall being removed to show the interior structure and the contents thereof, as well as the directional movement of the air in our circulatory system in the kiln.

Fig. II is a plan view of the surrounding walls and the basement-space of a dry kiln, with openair vents in the front wall thereof, showing the steam-boiler-radiator adapted for service in a dry kiln using our new air-circulatory system.

Fig. III is a front e e a i n. of a d y kiln designed and constructed to use our new air-cirulatory system, showing the fan for forcing the fresh outer air into the upper portion of the kiln and the vents to the open air in the lower part of the front wall and above them the sliding front door for the entrance of the lumber-trucks.

We will now describe our invention in detail, pointing out specifically the new and useful features and explaining the purposes and the operations of the individual parts and the combinations thereof throughout our invention, as illustrated in the accompanying drawing hereinabove described, in which similar letters and characters refer to similar parts throughout the several views.

Of the interior of our dry kiln, the upper part I I above the rail-track 4 and the basement 10 below said rail-track, are enclosed by means of the heavy walls, lb, lb, the basement floor, the thick roof la and the heavy end-doors, 6, 6. Below the rail-track 4 and some distance about the basement floor, is anchored on the stays 2b, 2b, as shown in Fig. I the steam-radiator made up of a plurality of steam-pipes, 2, 2, and their manifolds, 2a, 211 shown in Fig. II.

The lumber-trucks, 3, 3, mounted upon their rollers, 3a, 3a, are adapted to roll on the railtrack 4; and when they are properly loaded with the green lumber, they occupy most of the space in the upper part I of the kiln. These lumber-trucks are loaded with the green lumber near the front door 8, outside the kiln and then pushed into the kiln, usually one truck at a time, and the front door 6 closed at once. This truck for a certain length of time is allowed to remain unmoved in this front end of the kiln where the temperature is not so high as it is farther on in the kiln; for green lumber should not, when first moved into a dry kiln, be submitted to the high temperature later required in drying it. Consequently, we have designed a radiator with comparatively fewer heat-generating pipes along the front end thereof, as shown in Fig. II. After a day or two, this truck of green lumber will be moved into the next place in the kiln and the truck of lumber in the back end of the kiln will be moved out, fully cured and ready for use. Another truck of green lumber will be moved into the front end of the kiln to be moved along in its turn in the kiln until it is cured and moved out at the back end of the kiln.

Now, our air-circulatory system for the rapid drying of green lumber, is accomplished by means of the detail construction of our dry kiln, as previously described in combination with the other features, the functions of which we will herein explain.

Inside the front wall of the kiln, over the front door 6, we have installed an electrically-driven fan 1 together with its operative motor 8, adapted to force a predetermined amount of the fresh, outer air into and all along the upper portion of the kiln above the loaded lumber-trucks, 3, 3, as indicated by the uppermost arrows of longitudinal direction, as shown in Fig. I.

A large portion of this cool, fresh air passes along over these lumber-trucks to the back end of the kiln and being cooler than the heated air in the kiln, settles down behind the back truck, from which space it is drawn under the steam radiator and mingles promiscuously with the air in the kiln around the hot pipes, 2, 2, 2a, 2a, where it is heated to a desirable temperature. Then, by reason of the upward sweep of this heated air, it circulates energetically in upward currents, eddying all through the lumber on the trucks, 3, 3, above the rail-track 4, as indicated by the arrows marking undulatory upward-curving courses. This heated air now moisture-laden from the green lumber, passes out through the tops of the loaded lumber-trucks where it is forced longitudinally back over the tops of said loaded trucks, 3, 3, as it mingles with the forceful current of fresh outer air driven inward by the revolving fan 1 and flowing towards the rear of the kiln, which We have previously described. From the sheavewheel 8a of the electric motor 8 adapted to operate the fan I, the driving belt 9 extends to the sheave-wheel 1a on the fan shaft.

The introduction of this continuous supply of the fresh outer air, which we have prepared our dry kiln to receive and mingle promiscuously with the heated air in the kiln effectually prevents the formation of checks, cracks or internal fissures in the lumber, invisible on the surface, a condition sometimes called hollowhorned. These injurious conditions are developed in lumber frequently in dry kilns not properly and adequately furnished with the fresh outer air. When the outer air is admitted through ports in the lower portions of the kiln and vents are provided near the top of said kiln, unfavorable atmospheric conditions develop in the kiln, either delaying and prolonging the process of drying or subjecting the lumber therein to the danger of cracking, as explained above.

But when the dry kiln is constructed and equipped for operation according to the construction and equipment of our invention for the introduction of a certain amount of fresh, outer air into that portion of the kiln above the lumbertrucks to pass back along over the trucks to the rear of the kiln and down under the horizontal radiator mingling with heated air of the kiln, the lumber can be dried out more rapidly and safely than in any of the former types of kilns. The dampered outlet vents, 5, 5, in the lower portion of the front wall of the kiln allow the cool, moisture-laden vapors from the drying green lumber to pass out forced by the new, fresh, outer air driven in by the fan 1 operatively anchored in the fan-cylinder 1b fitted through the upper part of the front wall with its outer end securely braced by means of the side braces, 10, 70, shown in Fig. III.

However, it should be understood that the specific details of parts of our invention which we have herein illustrated and described, are not to be considered as limitations in the construction of our improved air-circulatory system for dry kilns; and that, while keeping Within the scope of our invention and claim, any desirable modification of these details may be made to facilitate production of our dry kilns, or to economize in the fabrication of the parts thereof, provided we keep within the spirit of said invention.

Now, having described the various features of our invention, the detailed construction, arrangement, purposes and method of operation, we wish to explain that those features and combinations of our invention that we consider new and representative of utility and efficiency, and on which we desire Letters Patent granted to us, we have hereinbelow set forth and specifically described in the following claim.

We claim:-

A dry kiln of the character described, having an interior consisting of an upper part and a basement space; a rail-track running horizontally through said kiln between the upper part and said basement; lumber-trucks adapted to run on said rail-track and designed to hold green lumber to be dried; heavy walls, having thick sliding doors at either end thereof, a thick roof and a basement floor, all adapted to enclose these parts for their normal functions; a steam-boiler-radiator, consisting of a plurality of parallel steampipes and their manifolds, extending horizontally the length and breadth of said kiln and adapted to heat the air of the kiln to complete its circulation through the lumber on trucks above; an elec tric fan installed in the upper part of the front wall of the kiln, adapted to force a predetermined quantity of the fresh outer air into the kiln along over the tops of said loaded trucks to the rear of the kiln and down under said radiator, to be heated for circulation through the loads of lumber 0n the trucks above, as We have above explained.

CHARLES PHILLIPS. GEORGE M. HARRIS. 

